Mid Klamath Invasive Plant Identification Guide

Identifying Characteristics:

Flower color: pink-purple

Flowers: July to September

Stems: partly winged; spiny. Multiple flower-heads at end of stems.

Plant height: ranges from about 1 foot to 6 feet

Leaves: very spiny

Growth habit: annual/biennial

Occurrence: Open disturbed sites, roadsides, fields, pastures, hillsides, rangeland, forest openings. Prefers warm, dry climate areas. Tolerates a wide range of soil types.

Giant plumeless thistle (Carduus acanthoides) is found in only one location in the mid-Klamath. This is also the only known location in all of Siskiyou County.

Notes: Plant spreads by seed only. Seeds are viable for up to seven years, and germinate aggressively.

More Info: California Invasive Plant Council

Identifying Characteristics:

Flower color: pink-purple

Flowers: May to July

Stems: partly winged; spiny. Multiple flower-heads at end of stems.

Plant height: ranges from about 1 foot to 6 feet

Leaves: very spiny, lobed, wooly hairs underneath smooth on top

Seeds: small with a downy pappus which assists in wind dispersal

Growth habit: annual

Occurrence: Open disturbed sites, roadsides, fields, pastures, hillsides, rangeland, forest openings. Prefers warm, dry climate areas. Tolerates a wide range of soil types.

Italian thistle is not common in the Mid Klamath. It is present in Weitchpec, isolated sites along the highway between Happy Camp and Somes Bar, and on a forest road near the headwaters of Rock Creek. There is also a population in Forks of Salmon.

Notes: Plant spreads by seed only. Seeds are viable for up to seven years, and germinate aggressively.

More Info: California Invasive Plant Council

Identifying Characteristics:

Flower color: white, in dense clusters near the ends of branches

Flowers: June to August

Plant height: one to six feet

Leaves: lanceolate, bright green to gray green, smooth to toothed margin; basal leaves larger than upper leaves

Fruit: two-seeded capsule

Seeds: reddish-brown, round, flat, slightly hairy, about 1/16 inch long

Growth habit: perennial

Occurrence: Grows in waste areas, wet areas, ditches, roadsides, croplands, along waterways, and dry habitats like road cuts and fills.

Notes: Robust, deep-seated spreading roots and numerous seeds make this plant very difficult to control. Outcompetes native vegetation and crops. Attempts at mechanical removal spreads the plant by distributing seeds and dividing the rhizomes. An effective method of control is early detection and manual removal. To treat established populations, apply thick mulch mats and manually remove juvenile plants. Plant is spreading downriver and has been seen with heavy infestations in Seiad Valley, and smaller patches have been noted in Happy Camp. Now is the time to prevent this weed from staking its claim downriver.

More Info: California Invasive Plant Council

Identifying Characteristics:

Stems: ascending to erect, with fine white hairs

Leaves: oblong to narrowly elliptic, alternate, 3 inches long, broadly rounded leaf tips

Flower color: green to geenish-yellow

Bracts: yellow-green

Flowers: April to September

Plant height: 1-4 feet

Growth habit: perennial

Toxicity: All spurges exude a milky white latex. This latex can cause severe skin reactions. When handling oblong spurge, it is recommended to wear gloves and long sleeves and to avoid touching eyes after contact.

Occurrence: Oblong spurge can survive under a wide range of unfavorable plant conditions. In the mid-Klamath, it is commonly found in sandy soils on river bars, under partial shade of willows.

Populations of oblong spurge are contained to river bars around Somes Bar and Orleans.

Notes: This plant is less aggressive than leafy spurge. It does not reproduce by rhizome, but shows rapid distribution by seed. It has a large taproot which can be difficult to remove completely. Recommend hand pulling while soil is moist; this removal will be followed by an overwhelming amount of seedlings, some of which will reach maturity within the same year.

More Info: California Invasive Plant Council

Identifying Characteristics:

Flower color: pinkish purple with fuzzy white center

Flowers: July to September

Plant height: 8 inches to 6 feet

Stems: One or more, branching

Basal leaves: feathery, lobed

Bracts: tipped with dark tinged

Growth habit: biennial or short-lived perennial with stout taproot

Similar to Meadow knapweed, also found in the Mid Klamath area

Occurrence: From 400-4000' elevation, adaptable to a variety of habitats. Moist areas, dry roadsides, in the shade or sun.

Spotted knapweed has small, isolated occurrences along the Klamath River and upslope sites. Most of these are in and around Orleans.

Notes: Spotted and Diffuse Knapweed were first discovered by the USFS on the Salmon River in 1997, with concentrated populations in the Kelly Bar vicinity on the North Fork Salmon River. Both species are rated "Class A" species, which mandates eradication as described in county and state health codes. Local land managers promoted the status quo management approach, which was to apply several different herbicides for at least five years. In response, the local community launched one of the most effective noxious weed efforts known in the region, significantly reducing or eliminating knapweed plant concentrations in over 250 sites. This program was taken up by MKWC volunteers on the Klamath River in 2001.

More Info: California Invasive Plant Council

Identifying Characteristics:

Flower color: bright yellow, solitary

Flowers: April to October

Stems: highly branched, green to reddish-brown, prostrate and spreading radially from the crown on open ground to erect when shaded or competing with other plants

Leaves: opposite, even-pinnate compound, ~ 1.5-2 inches long, with 3-7 leaflet pairs per leaf and a small extension at the tip

Seeds: extremely sharp, can puncture bicycle tires and shoes

Growth habit: annual

Occurrence: Disturbed places, roadsides, cultivated fields, yards, waste places, walk ways. Grows best on dry sandy soils, but tolerates most soil types. Intolerant of freezing temperatures.

Notes: Puncturevine has not been present in this area for very long. Now is the time to control the spread before the seed bank becomes unmanageable.

Most plants on the Klamath are found along the June high-water line (where a white, dried algal crust can be found) and in areas with sand between river rocks within 100' of the river.

This plant comes to us from Southern California, moving up through the Central Valley, where it is known to grow in extremely harsh urban environments such as abandoned parking lots and sidewalk cracks. Several individual plants were also noted in Happy Camp an urban setting. Interestingly enough, the plants had been sprayed with an herbicide and were brown and crispy.

More Info: California Invasive Plant Council

Identifying Characteristics:

Flower color: white to purple

Plant spreads via rhizomes (underground roots), that run 2-6" below soil level, and seed.

Similar to Spotted knapweed, also found in the Mid Klamath area

Occurrence: From 400-4000' elevation, adaptable to a variety of habitats. Moist areas, dry roadsides, in the shade or sun.

Indian Creek Road, north of Happy Camp, CA has patches of infestation along the road from mile markers 3 to 10. Fortunately there is only one place where a large infestation is growing near the Indian Creek (at the 10 mile mark).

There is also a large population in and around Weitchpec. This population is along the Highway 96 and 169, and on adjacent private properties. MKWC is currently working with the Yurok Tribe, CalTrans and private landowners to control the southernmost, known, population of meadow knapweed.

Notes: If meadow knapweed seeds make it to the water they can be transported throughout the watershed in one high water event. Automobiles passing along this road after seed heads form are also likely to transport this weed throughout the watershed. This infestation threatens to spread downriver.

More Info: California Invasive Plant Council

Identifying Characteristics:

Stems: erect, glabrous or hairy, when broken exude a milky latex

Leaves: linear to narrowly oblanceolate, alternate, 3 inches long, 1/4 inch wide, tips acute or rounded, margins smooth

Flower color: green to geenish-yellow

Bracts: yellow-green

Flowers: June to September

Plant height: 1-3 feet

Growth habit: perennial

Toxicity: All spurges exude a milky white latex. This latex can cause severe skin reactions. When handling leafy spurge, it is recommended to wear gloves and long sleeves and to avoid touching eyes after contact.

Occurrence: Leafy spurge can survive under a wide range of unfavorable plant conditions. However it spreads most rapidly in areas where cattle or other grass-preferring animals remove competing plants, permitting leafy spurge to take over by utilizing the advantages of shooting seeds and invading roots.

The leading edge of the Klamath River leafy spurge population is identified just down river of Orleans at the Ullathorne River Access. There are large infestations present on the Scott River and on the Klamath, upriver of Happy Camp.

Notes: Plants can send rhizomes (underground roots) up to 8' underground, making this plant extremely difficult to control if left untreated. Any part of the root that remains in the soil after digging will sprout a new shoot that same year, or the following year. Siskiyou County Agriculture is currently treating this plant with the herbicide glyphosate on private property on the Klamath and Scott Rivers.

More Info: California Invasive Plant Council

Identifying Characteristics:

Flower color: pink-purple, very fluffy

Flowers: June April to October

Stems: erect stems each spring, the stems often lie partly flat by summer

Plant height: typically 2 to 3 feet tall in our area (can reach 6 feet)

Leaves: very spiny, lobed, up to 6-8 inches long and ¾ to 1½ inches wide

Seeds: ¾ to 2 inches long, with a downy pappus which assists in wind dispersal

Growth habit: perennial

Occurrence: Open disturbed sites, roadsides, fields, pastures, hillsides, rangeland, forest openings. Also found along stream banks and in gardens. Does not tolerate deep shade or constantly wet soils. Tolerates a wide range of soil types, but grows best in moist soils.

Notes: Plant spreads via rhizomes (underground roots) and by seed. Perennial patches of Canada thistle are found as a clump of many interconnected plants. All other thistles in our area grow as a single stemmed plant. It has no trouble sending rhizomes in a maze directly under river rock.

More Info: California Invasive Plant Council